1. Field of the Invention
The present invention relates to an endoscope which includes an insertion portion to be inserted into a subject and is configured to allow a distal end rigid portion at a distal end of the insertion portion to be electrically conductive with a conductive component coupled to the distal end rigid portion.
2. Description of the Related Art
In recent years, endoscopes including an insertion portion configured to be inserted into a subject or object have been widely used in medical fields and industrial fields. The endoscope used in the medical fields is capable of observing an organ in a body cavity by inserting an elongated insertion portion into the body cavity as a subject and performing various treatments by using, as necessary, a treatment instrument inserted into an insertion channel for the treatment instrument that is included in the endoscope. In addition, the endoscope used in the industrial fields is capable of performing examination such as observation of flaws, corrosion and the like of a region to be examined in an object and various treatments with respect to the region by inserting an elongated insertion portion of the endoscope into the object such as a jet engine or piping in a factory.
A distal end side of the insertion portion of an endoscope is constituted of a distal end rigid portion made of a rigid member such as a metal material, and the distal end rigid portion is provided with an illumination system that irradiates a subject or an object with illumination light, an image pickup unit that picks up an optical image of a site to be examined illuminated with the illumination light, and the like. The image pickup unit disposed in the distal end rigid portion is connected to a GND which is floated by being insulated from other peripheral devices connected to the endoscope, so as to ensure electrical safety, and the metal member of the distal end rigid portion is also rendered equipotential, with the potential of the GND used as a common reference electric potential.
The distal end rigid portion is connected to the GND via a bendable bending portion coupled to the proximal end side of the distal end rigid portion. The bending portion is configured by coupling a plurality of metal bending pieces, and the distal end rigid portion is connected to the GND by allowing the bending portion and the distal end rigid portion to be electrically conductive with each other. The electrical conduction between the distal end rigid portion and the bending portion is generally ensured by the structure for fitting and fixing the distal-most bending piece of the bending portion to the distal end rigid portion as disclosed in Japanese Patent Application Laid-Open Publication No. 2001-128937 or an abutting structure for allowing components to abut each other.